1. Field of the Invention
The present invention relates to a resistive touch panel, and more particularly to a panel structure facilitating assembly and enhancing yield of a resistive touch panel.
2. Description of the Related Art
Recent technology trends have been toward touch screen devices using touch panels, which are either resistive touch panels or capacitive touch panels. The resistive touch panel for an electronic device, as shown in FIG. 6 and FIG. 7, has a bottom panel, a top panel, a first adhesive layer (904), a separating layer (905), a flexible circuit board (903), a solid film (92), a second adhesive layer (921) and a pattern layer.
The separating layer (905) and one end of the flexible circuit board (903) are sandwiched between the bottom and top panels by the first adhesive layer (904).
The bottom panel has a substrate (90), a lower conducting layer (901) and a plurality of first electrodes (902). The lower conducting layer (901) is formed on a top surface of the substrate (90). The first electrodes (902) are mounted on edges of a top surface of the lower conducting layer (901) and electronically connected with the end of the flexible circuit board (903) that is used to connect with an external control circuit inside the electronic device.
The top panel has a protective film (91), an upper conducting layer (911), a plurality of second electrodes (912) and an insulation layer (913). The upper conducting layer (911) is formed on a bottom surface of the protective film (91). The second electrodes (912) are mounted on edges of a bottom surface of the upper conducting layer (911) and electrically connect with the end of the flexible circuit board (903). The insulation layer (913) is mounted on the second electrode (912) and underneath the bottom surface of the upper conducting layer (911).
For some specific applications of the electronic device, the touch panel has patterns directly added thereon to mark functions of the applications. Therefore, a user can touch the functional patterns on the touch panel to start the corresponding functions of the electronic device. To achieve this objective, the printing ink layer is used. The functional patterns are printed on a bottom surface of the solid film (92), and the solid film (92) is mounted on a top surface of the protective film (91) by the second adhesive layer (921).
However, air bubbles are easily generated between the solid film (92) and the protective film (91) of the top panel when the solid film (92) is adhered to the second adhesive layer (921) on the top panel. Therefore, an uneven surface of the resistive touch panel easily occurs and further affects the operating performance of the resistive touch panel. Once the uneven issue occurs, the defective goods must be rejected causing an increase in production cost. Therefore, the structure of the resistive touch panel needs to be further refined.